CHRIS is an AO hyperspectral instrument whose objective is the collection of BRDF (Bidirectional Reflectance Distribution Function) data for a better understanding of spectral reflectances. CHRIS is the prime instrument of the PROBA-1 mission. The technology objective is to explore the capabilities of imaging spectrometers on agile small satellite platforms. CHRIS provides 19 spectral bands (fully programmable) in the VNIR range (400 - 1050 nm) at a GSD (Ground Sampling Distance) of 17 m. Each nominal image forms a square of 13 km x 13 km on the ground (at perigee). The observation of the square target area consists in 5 consecutive pushbroom scans by the single-line array detectors, each scan is executed at different view angles to the target within a 55º cone centered at the target zenith. The pushbroom velocity at the target must be reduced by a factor of 5 compared to nominal nadir-pointing velocity in order to increase optimal exposure time. CHRIS can be reconfigured to provide 63 spectral bands at a spatial resolution of about 34 m.The spectral band sets are 19 band read out at 17m GSD. The CHRIS design is capable of providing up to 150 channels over the spectral range of 400-1050 nm.